In many applications mesh-free particle simulations offer distinct advantages compared to grid-based finite element or finite volume methods. Mesh-free methods are both, an alternative and a complement. For example: the simulative investigation of granular materials, their transport in fluids or their interaction with structures or components.
From the user perspective the combination of mesh-free particles with grid-based codes, to make the respective strengths of both methods for an application usable, is our main focus. We provide our developments forth this link.
The class of particle codes here are on the one hand the DEM codes (DEM = 3D Discrete Element Method) and on the other hand, the SPH codes (SPH = 3D smoothed-particle hydrodynamics).
The coupling of DEM with structural mechanics (Finite Elements) is particularly attractive for modeling the contact of granular matter with flexible bodies. The coupling will take place at the surface of a body which is in contact with the granular material. The nodal-points of the coupled surface are known to both the DEM and the FEA program. In the simplest case, both programs use the same integration time step.
The DEM program sends the forces of the repulsion contact, cohesion and friction as nodal forces to the FEA program, which then calculates the displacements and velocities at nodal points and returns the values to the DEM program. The displacements affect the shape of the elastic structure in the contact with granular matter, which in turn causes changes in the nodal forces.
The coupling between SPH codes and structural mechanics corresponds to a classical fluid-structure interaction (FSI), but the mesh- free SPH code is not subject to the limitations of the mesh-based flow-codes.